JPH0214578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to an improvement in a planetary friction type transmission.

[Prior art]

This is the first known device of this type.
This will be explained with reference to FIGS. In the figure, 1 is a high-speed shaft that is connected to a drive source such as an electric motor to rotate, 1a is a thrust receiver connected to one end of this high-speed shaft 1, and 1b is equidistantly spaced on the inner end surface of this thrust receiver 1a. 2 is a thrust receiving plate that is fitted onto the high-speed shaft 1 via a key 3 and faces the thrust receiving body 1a at a predetermined distance; 2a is this thrust receiving plate; 2, three pressure receiving recesses formed at equal intervals on the surface facing the three pressure receiving recesses 1b of the thrust receiving plate 1a; 4, a retaining ring fitted to the high speed shaft 1; 2 from moving toward the drive source side. Reference numerals 5 and 6 denote a pair of sun rollers having a conical ladder shape, which are loosely fitted in opposition between the thrust receiver 1a and the thrust receiver plate 2 of the high-speed shaft 1, and 5a and 6a are the pair of sun rollers. Three pressure receiving recesses are formed at equal intervals in the portions of the thrust receiving body 1a and the thrust receiving plate 2 facing the three pressure receiving recesses 1b and 2a, and 7 is the pressure receiving recess 1b. , 5a; 8, three copper balls fitted between the pressure receiving recesses 2a, 6a; 9, circumscribing the outer peripheral surfaces of the pair of sun rollers 5, 6, respectively. and 4 equally spaced
10 is a hollow metal fitted to the inner peripheral surface of the planetary roller 9; 11 is loosely fitted to the inner periphery of the metal 10, and the planetary roller 9 is A rotatably supported planetary roller shaft 12 is a low speed shaft connected to a load, and is disposed on the same axis as the high speed shaft 1 and the sun rollers 5 and 6. 12a is a flat plate portion connected to the low-speed shaft 12, into which the planetary roller shaft 11 is fitted. 13 is a fixing ring inscribed in the outer circumferential surface of each of the four planetary rollers 9 and whose inner circumferential surface is formed in a concave curve; 13a is a keyway carved on the outer edge of the fixing ring 13; 14; 14a is a casing into which the fixing ring 13 is fitted on the inner periphery; 14a is a keyway carved into the inner periphery of the casing 14; 15 is the keyway 1;
3a and 14a prevent rotation of the fixing ring 13. Reference numeral 16 denotes a retaining ring fitted to the inner circumferential surface of the housing 14, which engages with one end of the fixing ring 13 and locks the fixing ring 13.
This prevents axial movement of the

Next, the operation of the device configured as described above will be explained. Now, when the high-speed shaft 1 is rotated by the drive source with the high-speed shaft 1 as the input shaft and the low-speed shaft 12 as the output shaft, the thrust receiver 1a, the retaining ring 4, and the thrust receiver plate 2 connected to the high-speed shaft 1 are integrated. rotate. When the thrust receiver 1a and the thrust receiver plate 2 rotate, the copper balls 7 and 8
A pair of sun rollers 5, 6 → planetary roller 9
→The rotational force is transmitted to the fixed ring 13. In this case, the fixed ring 13 is connected to the housing 14 with the key 15, so the planetary roller 9 is in circumscribed contact with the sun rollers 5 and 6 and inscribed with the fixed ring 13, and rotates and revolves.
The low-speed shaft 12 rotates at the revolution speed of the planetary roller 9 and drives the load. In this case, the thrust applied to the sun rollers 5 and 6 changes depending on the magnitude of the load, but when the load is large, the thrust receiver 1a→copper ball 7→sun roller 5, and the thrust receiver plate 2→copper ball 8
→The thrust of the sun roller 6 increases, so the contact pressure between the sun rollers 5, 6 and the planetary rollers 9 increases, and the contact pressure between the planetary rollers 9 and the fixed ring 13 also increases, resulting in a large rotational force. This is transmitted to the low speed shaft 12 and drives a large load.

Conventional devices of this type are constructed and operated as described above, and therefore not only require high-precision machining of each component, but also have the drawbacks of complex structures, large numbers of parts, and large devices. Ta.

In addition, since the planetary roller is supported by the planetary roller shaft, it is supported on a cantilever and causes an uneven load.
The drawback was that sufficient torque transmission could not be achieved.

Furthermore, the gear ratio i by this device is i=N ₁ /N ₂ =D _I +D _S /D _S =1+D _I /D _S However, N ₁ : Number of revolutions of input shaft 1 N ₂ : Number of revolutions of output shaft 12 D _I : Inner diameter of the fixed ring 13 D _S : Outer diameter of the sun rollers 5 and 6, and the range of the speed ratio i was narrow, about 3 to 5. In addition, since each contact was a point contact, high Hertzian surface pressure was generated, resulting in a product with low transmission capacity.

[Embodiments of the invention]

The present invention has been made in an attempt to eliminate such drawbacks, and one embodiment of the present invention will be described below with reference to FIGS. 3 to 5.

In FIG. 3, 20 is an input shaft that is connected to a drive source and rotates, 21 is a conical wheel provided at the end of the input shaft 20, and 22 is an input shaft that supports the input shaft 20 via bearings 23 and 24. 1 bracket,
25 is a housing fixed to the end face of the bracket 22, 26 is a rolling wheel (hereinafter referred to as a fixed plate) fixed to the housing 25, and 27 is the conical wheel 2.
1 and three steel balls pressed against the fixed plate 26, 28 is an output shaft, 28a is a spline shaft provided on the output shaft 28, 29 supports the output shaft 28 via bearings 30 and 31, and the housing 25 A second bracket 32 is fixed to the other end of the spline shaft 2.
Holding discs (hereinafter referred to as carriers) 32a that are fitted into the carriers 8a and movable in the axial direction are provided at three locations on each side of the carrier 32, and have an inclination angle with respect to the circumferential direction to hold the steel balls. recessed grooves each in contact with 27;
33 is an elastic body that presses the carrier 32 toward the input shaft, and 28b is a stopper that limits the movement of the carrier 32 toward the output side.

FIG. 4 is a side view of the carrier 32 seen from the input shaft side, and FIG. 5 is a sectional view taken along the line in FIG. 32b indicates a contour line within the recessed groove 32a.

Next, the contact between the steel balls 27 will be explained with reference to FIG. In FIG. 6, the center O of the steel ball 27 is the origin, the axial direction of the rotating shaft 20 is the X axis, the center O of the steel ball 27 is the origin, the radial direction is the Z axis, and the contact point between the conical wheel 21 and the steel ball 27. A, recess groove 3 of carrier 32
Let B be the pressure contact point between 2a and the steel ball 27, C be the pressure contact point between the fixed plate 26 and the steel ball 27, and let the pressing forces at each pressure contact point A, B, and C be N _A , N _B , and N _C . Further, pressure contact point B has an angle θ with respect to the X axis, and the OB line is set as the η axis.
In other words, the pressure contact points A and C between the steel ball 27, the conical wheel 21, and the fixed plate 26 are on the X-Z plane, and the pressure contact point B with the carrier 32 is on the η- It is located on the Z plane, and due to the unidirectional rotational force from the conical wheel 21, three pressure contact points A, B, and C are wedged in the circumferential direction. However, even though the steel ball 27 is wedged in the circumferential direction, it is free to rotate about the η-axis, and due to the rotational force of the conical wheel 21, it becomes a planetary motion that revolves and rotates, and the fixed plate 26, the carrier 32 is decelerated.

This reduction ratio is as follows, and by arbitrarily setting the position of the stopper portion 28b that restricts the movement of the carrier 32, the positions of the pressure contact points A, B, and C can be changed, and a wide range of transmission ratios can be achieved. You will get it.

i=N _IN /N _OUT =1+r ₁ /R ₁ ×R ₂ /r ₂ However, the number of revolutions of the conical wheel 21...N _IN The number of revolutions of the carrier 32...N _OUT The radius from the rotating shaft 20 to point A...R ₁ Radius from rotating shaft 20 to point C...R ₂ Radius from η axis of steel ball 27 to point A...r ₁ Radius from η axis of steel ball 27 to point C...r ₂ Next, the operation will be explained. When no rotational force is transmitted from the drive source, the carrier 32 is pushed toward the input shaft by the pressing force of the elastic body 33, and the steel ball 27 is in contact with the recessed groove 32a at its deepest point.

Next, when the input shaft 20 is started, rotational force is applied,
The pressing force of each contact point A, B, C changes. The axial thrust of the contact B due to the rotational force overcomes the pressing force of the elastic body 33, and the carrier 32 slides toward the output shaft. At this time, the carrier 32 moves until it comes into contact with the stopper portion 28b, and the steel ball 27 moves along the slope of the recessed groove 32a. carrier 32
When it comes into contact with the stopper portion 28b, torque is transmitted at the contacts A, B, and C using a pressing force corresponding to the rotational force. The rotation of the input shaft 20 is then decelerated by the planetary motion of the steel balls 27 and transmitted to the output shaft 28.

〔Effect of the invention〕

As described above, according to the present invention, a small, simple, and inexpensive transmission with a small number of parts is provided by a mechanism composed of steel balls, a conical wheel, a fixed plate, a carrier having a concave groove with an inclined angle, and an elastic body. It will be possible. Note that when the transmission force is small, the recessed groove is not necessary, and the transmission force corresponding to the elastic force of the elastic body is transmitted. Also, the force acting on the steel ball is 3
With the balance of force at a point, the pressing force corresponds to the rotational force,
In addition, the minimum pressing force necessary for frictional transmission is generated. By arbitrarily setting the position of the stopper portion of the carrier, the three pressure contact points can be changed to change the gear ratio, and a wide range of gear ratios can be obtained. Note that even if the input and output shafts are reversed, the operation is the same, except that the gear ratio becomes a reciprocal.

[Brief explanation of drawings]

Fig. 1 is a partial side view of a conventional planetary friction type transmission, Fig. 2 is a cross-sectional view taken from Fig. 1, Fig. 3 is a sectional view showing an embodiment of the present invention, and Fig. 4 is a cross-sectional view of a carrier. 5 is a side view, FIG. 5 is a cross-sectional view taken from FIG. 4, and FIG. 6 is an explanatory diagram of the operation of the present invention. In the figure, 20 is an input shaft, 21 is a conical wheel, 22, 2
9 is a bracket, 25 is a housing, 26 is a fixed plate, 27 is a steel ball, 28 is an output shaft, 32 is a carrier, and 33 is an elastic body. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. A conical wheel, a rolling wheel arranged concentrically with the conical wheel and having a conical surface on its inner periphery, a sphere that comes into contact with the conical wheel and the conical surface of the rolling wheel, and a conical wheel with respect to the circumferential direction of the conical wheel. a holding disk having a side surface that abuts at a predetermined inclination angle; and an elastic body that presses any one of the conical wheel, rolling wheel, and holding disk against the spherical body. Friction type transmission. 2. The planetary friction type transmission according to claim 1, characterized in that the angle of inclination is in the range of 2° to 15°. 3. The planetary friction transmission according to claim 1 or 2, wherein any one of a conical wheel, a rolling wheel, and a holding disk is fixed.